1. Field of the Invention
The present invention relates to a process of treating a nonwoven web with an elastomeric binder. More particularly the invention relates to treating a spunbonded polyester web to impart improved tufting properties.
2. Description of Related Art
A tufted carpet is generally manufactured by inserting reciprocating needles threaded with a face yarn through a primary backing material to form loops or tufts of yarn in the backing. The quality, appearance and dimensional stability of tufted carpets depends in large part on the properties of the primary backing.
Primary backings are usually produced from woven or nonwoven materials. Tufting into nonwoven materials is more difficult than tufting into woven materials. A woven fabric will open within the weave to accept the tufting needle and yarn and will then close around the tufted yarn after the needle has retracted. The closing property of woven fabrics provides a firm grip on the yarn in the opening. The yarn must remain in the opening until adhesive is applied to secure the yarn in place.
On the other hand, nonwovens have no weave to open and close nor do the individual filaments have a memory to return to the original state. Tufting into a nonwoven backing usually results in creating an opening large enough to accept the tufting needle and yarn. However, when the needle retracts, the opening does not close tightly around the yarn and remains larger than necessary to grip the yarn. The result is a condition in which the tufting yarn may slip out of the opening creating defects and necessitating repair and reworking.
Nonwoven backing materials typically are spunbonded or spunlaid webs formed from thermoplastic polymers such as polyolefins, polyesters and blends of these materials. Spunbonding is a process which generally involves feeding a thermoplastic polymer into an extruder, feeding the extruded molten polymer through a spinneret to form continuous filaments, and laying down the extruded filaments on a moving conveyor belt to form a nonwoven web of randomly arranged continuous filaments. In the lay-down process, desired orientation may be imparted to the filaments by various means such as rotation of the spinneret, electrical charges, introduction of controlled airstreams, varying the speed of the conveyor belt, etc. The individual entangled filaments in the nonwoven web are then bonded primarily at filament cross-over points by thermal or chemical or mechanical treatments. The spunbonded web is then wound up in a roll form.
During the carpet tufting process, hundreds of tufting needles threaded with yarn are inserted into the primary backing material with each stroke of the needle bar. Each needle penetrates the backing material creating an opening and then retracts leaving a loop of yarn in each opening. Each needle then moves to the next insertion point.
During the tufting process, the primary backing material must provide two very important characteristics: insertion resistance to the tufting needles and the ability to grip and hold the yarn loop (tuft) in place after the needles retract. Optimally, it would be most desirable to have a backing material which has minimal insertion resistance and maximum tuft grip at any point. However, mechanical and chemical properties of the web material necessitate a designed trade-off of both characteristics. That is to say, a high gripping force would likely require a high penetration force. Conversely, a low penetration force usually results in a poor or weak tuft gripping force. A primary backing which combines a low insertion resistance with a high gripping force would be highly desirable.
It is an object of the invention to produce a nonwoven web suitable for use as a carpet backing material which has improved tuft gripping characteristics.
Another object of the invention is a process for improving the tuft gripping properties of a spunbonded or spunlaid polyester fabric.
Still another object of the invention is an improved process of producing a tufted carpet.
These and other objectives of the present invention will become readily apparent upon a review of the present disclosure.